How do you do a 1000 reviews a day and don’t burn out? Judging by my stats you must have at least 12k cards easily.
Currently my process looks like this. I use jpdb (to save time). I try to read something every day and add every non obvious word as a new card. By non obvious I mean a word that I did not guess the meaning and reading correctly on first try, or tricky words with awful rendaku traps or obscure kanji readings. For obvious words I either ignore them, or mark them as “never forget” to boost my ego.
I usually do reviews once or twice a day (jpdb gives you new cards with precision to the minute which has its merits and demerits). Currently with 3k cards in the learning I have around 200 cards to review a day.
Just until two weeks ago I was super hardcore about adding new cards to reviews because I had this goal that I would be alright-fluent next year, so each card I added as new card that day I would then add to reviews (start learning them), which was often up to 70 even, but after reading the book and then a VN I got humbled really bad with my goal and set a hard limit to 20 new cards a day, because there is no way I could keep up the pace for the years to come. As a result my new cards keep piling up faster than I can add them to learning phase, but it stopped bothering me as much as it did. I don’t think I will increase the amount ever, it’s more likely I will decrease it. In the end spending more time on reading and listening is more fun and effective.
tldr 20 new cards with around 200 reviews a day. This is how my pile looks at this moment: